I think I am going to buy the same converter for my
boler. It has 3 openings for breakers but you can buy tandem breakers that have two circuit breakers that are the same size as one standard breaker, thus allowing you to have 6 breakers installed, since one of these must be the main breaker that feeds the others it leaves you with 5 branch breakers if you install three tandem breaker units. What I plan to do is buy a standard single 30 amp breaker to act as the main breaker and two tandem breakers, 15 amp per circuit. This will give me one large main breaker and then 4 branch breakers on tandem units. Do keep in mind that the 12 volt converter does require one breaker for its power. In my installation I will have three circuits remaining for the rest of the trailer, one for interior receptacles, one for the
fridge, and one for the exterior receptacle I plan to install.
The installation manual for that converter lists the types of breakers that will fit, the Square D homeline breakers are easily found in the standard and tandem sizes at any Home Depot or
electrical supplier. The HOM models are the single circuit breakers and the HOMT models are the tandem ones. You do not need arc fault breakers in the trailer, and also a one circuit arc fault breaker takes up two breaker slots and would take up almost all the space in the converter. One thing I like to do is install GFCI receptacles in the trailer, which are safer around water and are especially important since my receptacle in the trailer is only 6 inches from the sink.